The present invention relates to drive wheel conveyors, for example, for use in assembly lines for motor vehicles or household electric appliances for transporting parts carrying pallets or the like so that the pallet or the like can be temporarily stopped during transport.
Such conveyors are already known which comprise, for example as disclosed in JP-A 63-77911, a side frame of U-shaped cross section having an inner side wall, an outer side wall and a bottom wall and extending in a transport direction, a drive shaft supported by the inner and outer side walls so as to extend through the side frame transversely thereof, a sprocket fixed to the drive shaft and positioned between the inner and outer side walls, an endless drive chain in engagement with the sprocket and disposed inside the side frame so as to be movable in circulation, and a transport wheel having the drive shaft fitted in a shaft bore therein between the inner side wall and the sprocket and drivable by frictional resistance between the bore-defining inner peripheral surface of the wheel and the outer surface of the drive shaft.
When the conveyor is viewed from above, the transport drive mechanism including the sprocket and the drive chain is left exposed. This entails the likelihood that the worker will be caught by the drive mechanism, which is therefore hazardous. Further if a bolt, rubbish, or like extraneous matter, falls into the frame and engages in the drive mechanism, a problem will occur. Another problem is encountered in that the drive mechansim spatters oil on the worker or the workpiece being transported.